When the beautiful game does not suffice, sometimes the blunt object will have to do and they come no blunter than John Terry's forehead. It was an old-fashioned centre-back's header from the Chelsea captain that settled matters last night, but then you take what you can get against a side as shamelessly defensive as Roma.

Later even Luiz Felipe Scolari was talked into admitting that this was hardly the most scintillating Chelsea performance Stamford Bridge has witnessed this season, but do not be fooled by all the talk about winning ugly. Great teams like Chelsea do not ride their luck – you would not dare to against a team as predatory as Roma – instead they broke their opposition down piece-by-piece and took their chance when it presented itself.

Terry nipped in at the near post to nod in Frank Lampard's corner 13 minutes from time and, this being Terry, almost injured himself as he landed awkwardly on his right leg. Until then, Chelsea had found all the normal routes to goal blocked: neither full-back permitted to overlap, no space for Nicolas Anelka to run into, so eventually they took the simplest option of all. This was the kind of Champions League game English teams once lost – those tense nights when the opposition pounced to steal a victory.

But Chelsea are no Champions League naïves. Scolari had warned that his team's football would not always be beautiful although there was a discipline about last night's performance that was beguiling. "I told the players that this would be a tactical game," Scolari said. "I said if we were to pressure this team and make a mistake, we might lose the game. We needed to be calm and score the first goal. After that, it would give us more space. I said it would be a game between two beautiful teams. Sometimes 1-0 is more important than 5-0."

Chelsea are top of Champions League Group A with seven points although defeat away to Roma on 4 November will make life awkward for them. Fail there and they still have to play Bordeaux in France and dispose of the Romanians CFR Cluj at Stamford Bridge. Composure will be required in Rome where, as Scolari pointed out, Victor Spalletti's team will have to be rather more adventurous than they were last night.

Despite the injuries that have plagued Terry's involvement with England this season, he has played every one of Chelsea's games and is a useful man to have around the penalty area when his team require a goal. "When I was with Portugal and we played England, I was afraid when Terry came up to our area for corner kicks," Scolari said. "I would say to my players 'Look, this player is decisive. We need to look at him because, if he touches the ball, it will be dangerous for us'. Now I'm here and I tell Terry to do that for us. He got to the ball and it was a big moment for us."

This new version of Chelsea have Scolari's passion for attacking football running through them but they also have the ice-cold discipline of Jose Mourinho's more prosaic instincts. Roma have the discipline but, on last night's evidence, none of the flair. For much of the game they were content to allow Francesco Totti to forage alone up front chasing lost causes. There would be outrage in this country if Manchester United made Wayne Rooney do the same.

For a team currently dawdling along at 14th in Serie A, you could not, however, fault Roma for their preparation. They shut down Chelsea at every opportunity and negated the damage that Lampard and Deco would normally expect to inflict even though the former was always in the game. He clipped the angle of post and bar with a shot on 23 minutes.

Only once did Chelsea really look threatened when, in the first half, Totti played a ball through to the Montenegro international Mirko Vucinic who was set to shoot when Terry came crashing in to deflect the ball away. On nights such as these, Chelsea miss the injured Didier Drogba. When he is fit – and, more importantly, up for a battle – it is Drogba around whom things happen. Anelka just does not inspire the same uncertainty in centre-halves.

On the hour Salomon Kalou squandered a very promising free header from Lampard's free-kick from the right. Terry did not make the same mistake when he scored the winner with 13 minutes remaining, running in at the near post to head the ball across the goalkeeper Doni and into the far corner. Later Lampard's blistering free-kick from the right side was tipped over by the Roma goalkeeper.

Against Liverpool on Sunday, Scolari said that he hoped it would be a different kind of game. "Yes, I want to play beautiful football against Liverpool," Scolari said. "They are a strong team and they don't fight for 90 minutes, but for 100 minutes. They've won four games this season [with goals] after the 85th minute. We'll need to play very well and we'll need concentration until the referee says the game is over. We will try to play a beautiful game but, more important for us, is that, if we don't play that well, we'll need to score one or two goals to win the match."

How often have Chelsea relied upon their two east London boys Terry and Lampard to get them out of difficult situations? Both were excellent last night and they needed to be. Late on in the game, Roma opened up and we were afforded a glimpse of this game as it might have been with Chelsea's full-backs streaming forward and gaps appearing in the Italian team. By then, however, Chelsea had been forced to do it the hard way.